Conversion of hydrocarbons



Nov. 9, 1943. G. EGLOFF CONVERSION OF HYDROCARBONS Filed April 5, '1941 /aff Patented Nov. 9, 1943 UNITED STATES ritffrfENT OFFICE v Gustav Egloff, Chicago, Ill., assignor to niversal Oil Products Company, Chicago, Ill., a corporation of Delaware" Airpiication April a, 1941, serial No. 386,603`

` 7 claims7k (ci. 19e-1o) This invention in'general relates to the conversonof hydrocarbon oil and more particularly to a combination of inter-related and cooperative steps whereby maximum utilization of all com` ponents of not only the charging stock but also of the intermediate conversion products is obtained. According to the features of this process, selected fractions are individually treated under optimum conditions for the maximum ccnversion thereof and, in addition, Vvthe 'invention provides for the utilization of morehighly heated products to assist in the conversion and .vaporization of the less highly heatedV products.

The primary charging stockfwhich may comprise an oil boiling above the range of gasoline, is separated into relatively light and relatively heavy fractions. Each fraction is `separately heated under independently controlled cracking conditions. Simultaneously, a secondary charging stock, which may comprise an oil boiling sub-` stantially within the range of gasoline, is also separately heated under independently controlled reforming conditions. The'olefinic constituents of the gaseous products of the process are v.polymerized in the presence of suitable catalyst to produce additional quantities of high octane gasoline, As one primary feature of the invention, the residual gases remaining after thepolymerization operation,whichconsist mostly of propane and butanerbut may also 4include some higher =1 and lower boiling fractions, as well as any unconverted olenic constituents, are separately heated under more severe independently controlled cronditions to effect interaction between these 4gases for the production of additional quantities of `liquid products. This interaction may include various reactions as, for example, cracking, dehydrogenation, polymerization, alkylation, condensation, etc. Provision is also made for supplying the less reactive gaseous products of theY process to the same heating zone.Y These le'ssfreactive gases include hydrogen, methane, ethane, ethylene, etc. f

In addition, as another feature of the invention, the highly heated products are supplied to `the lower portion of the coke chamber to assist vcon'- version of the residual liquid therein-to cokefand also to assist liberation `andseparation of' the vaporous conversion products from the coking zone. Another advantage to this 'operation'isv the production of a less'volatile coke as oneV of the main products of the process. Y

As a further feature of the invention, 4the gasoline produced in the thermal crackingiand coking steps is blended with the gasoline produced in the polymerization step and the mixture is subjected to common stabilization whereby toproduce `a final product of the desired vapor pressure and of high octane value.

In one specific embodiment the invention comprises f'ractionating a primary charging stock in the presence of intermediate-conversion products to separate selected fractions comprising a relatively heavy combined feed, a relatively light combined feed, gasoline boiling vrange fractions, a fraction consisting predominently of .3- and 4- carbon atom molecules, and a lighter gas fraction, separately cracking said relatively heavy and light combined feeds under independently controlled conditions, simultaneously separately heating a secondary charging stock, introducing al1v of the heated products to 1a coke chamber, fractionating the vaporous conversion products evolved .in the coke chamber in the presence of the primary charging stock, as previously described, polymerizing the fraction consisting predominently of 3 and 4 carbon atomlmolecules, separating from the polymerization products the unconverted gases, separately heating these gases under independently controlled conditions, introducing the last mentioned heated stream into the lower portion of the coke chamber, combining the previously separated gasoline productsof the cracking and coking operation with the gasoline produced in the polymerization step and subjecting the mixture to common stabilization to produce'a final gasoline product ofthe desired vapor pressure and of high anti-knock value.

`'lihe term combined feed, as used throughout the specification; is intended to designate the mixture of charging stock and intermediate conversion products being supplied to the various heating coils of the process.

It is not intendedY to unnecessarily limit thc present invention to the complete combination of steps shown in the drawing and `described in the specification. Variouslesser combinations which are new in the present state of prior art are also comprised within the scope ofthe present invention. These lesser combinations may omit, for example,V the separate reforming step in one case, or in another case the commingling of the less reactive process gases with the residual paraffinic gases being supplied to the separateheatingtreatment.

. The accompanying diagrammatic drawing to further illustratethe present invention is essentially a flow diagram 'and is not drawn to any specific scale. Y

Referring to the drawing, the primary chargquently be described, into selected fractions come n prising a relatively heavy combined feed, a relatively light combined feed, a fraction boilingsub` stantially within the range ofgasoline,'a,fraction consisting predominantly of 3 and-4 carbon-atom molecules, and a lighter gaseous fraction.

Fractionator and separator 6 is illustrated, for the sake of simplicity, as one zone; It is'uriderstood that this may comprise separate zones,V

such as one or more separators, fractionators, condensingmeans; receivers, a`ccumulators; e'tc. In addition, theA conventionalV method'L of returning aA portion of the condensedv overhead product to serve as a cooling and reuiing' medium'has been omittedl for the sake ofv simplicity. It is further understood tlia'tthe fractionators and separators may contain the'` conventional baiiies, butmetrays, etc: l k

The heavyv combinedA feed' is withdrawn from chamberl'through lin'e'V 1 and'valve 8 to'pum'p'S wherefrdm it isusuppiied through line lnand valve I'I to heating coil' |2`^in furnace structure' lf3-1 Theou is preferably heated in Cou l2, depending'upon its characteristics, to a temperature of` S50-1050"` ata pressure of substantially atmospheric to 500'pouiidsor more; The heated products' are' withdrawn through line I4l and valve' |f5 and' are supplied' eitherv through' .line' I 6 andvalve' I-T to cokechamber Il!` or" through line I9; and/valve' 20 to cokek chamber 21..

Simultaneously', a secondary charging' stock, which' preferably' comprises ar distillate of substantially gf'iso'lir'ie boiling range, is introduced through` linev 22" an`d valve 23k to pumpV 24 Wherefr'om' itis' supplied through line` 25 and valve 26 to heating coil' 21 in furnace structure 28. The secondary charging' stock may comprise either material boilingupA to' substantially 400 F. or it may also"inc`lutle higher boiling fractions such as those of kerosene, or'the like. If the primary charging stock` comprises a topped crude, the secondary charging' stock may comprise the straight-run' gasoline fractions separated'from the' original crude oil. In certain instances, the secondary' charging" stock may have an end-boiling point of less than 400"` Thev oil suppl-led to heating coil 21 is heated. therein to a temperature ofA 950-1150 F. at a pressure of atmospheric to 1000- pounds, or more. The-heated products are supplied through line 29 and valve 30 and either throug-hline I6 and valve l1 to-cokechamber lll or through line I9: and-valve 20 to'coke chamber 2|.

The light combined feed is withdrawn from fractionator and separator 6- through line 3l and valve 32v to pump 33 wherefrom it is supplied through line 34 andvalve 35- to heating coill 35 in furnace structure 31. The light combined feed is heated in coil 36` to a temperature"` of 950-l150 F. at a pressure of atmospheric'. to 1000 pounds or more,E ,'Ihe'heated;productsl are withdrawn through-line 3B'v and valve-39 and are preferably supplied through line 40 andI Valve 4'I- to the lower portion of coke chamber I8 or; through or.- by` knownA non-catalytic methods.

line 42 and valve 43 to the lower portion of coke chamber 2l. Alternatively, when desired, the heated products from coil 21 may be supplied to the lower portion of the coke chambers and the heated products from coil 36 may be supplied to the upper portion of the coke chambers. In certain instances, it may be desirable to supply the heatedproductsfrom bothy coils 21. and 36 to the lower portion of theI coke chambers. In any event, it is preferable to introduce the more highly heated products to the lower portion of the coke chambers and this will depend upon the characteristicsl'of the oil streams being supplied to these. coils. The products supplied to the lowerlpir'tib'ny ofi the coke chambers serve two iniportantpurposes; namely, the furnishing of additionalY heat to assist the coking operation and'- a'flso to a'ssi'stin the separation within and withdrawal from the coke chambers of the vaporous conversion products.

'A'lthoug-hlf tvvo` coking' chambers are shownA in thedraWin'gVit isi understood, ofcourse, that one orthre'e' or rnore'maybev employed. When two or-'morerar'e employedf theyl are preferablyv alternatelyi operated so that one or more chambers may'be#iniser-vicev while-coke from' thev other, or others@isloeing removed. Lines 44*V and 46, controlledbyvalves-45'and 4'1, respectively, are conventionall-andfiare providedfor the purpose of either"intr`o'di1cng steam or other materials to assi'stirily clean'in'g` the cokechambers, or for the w'itli'diavl'ral of any-'liquid condensate at anytime from the cokeclfia'mbers'I vThe vaporous products evolvedI in thefcokerchambers are Withdrawn therefrom' throughl linel 48 and valve 49 or thrugh' line 50': and'valve` 5| and are supplied through line*52tofractionator and separator 6,

wherein they undergoi fractionation and separatilo'r'fjin"y c'oi'nrningl'edv state with the primary 'charging' stock, as previously described.

The fraction: honing substantiany within the range'of' gasoline iswithdrawn from fractionator and'separator'6throughline 53 and valve 54 to pumps wherefrom it is supplied through line 56 andfvalve 5.7 to stabilizer 58. The operation of the'fstahili'zer'will be subsequently described.

The gaseous ,fractionsconsisting-predominantly of 3`La`n`dl4 carbon atom molecules are-withdrawn I'rorirv column 6'. throughline- 59 and valve 60 to pump. 6lwherefrom they are supplied through line62and.valve63 toa polymerization operation. vPolymerization. of the olens may be effected inf the presence of any suitable catalyst The catalysts,.-When. employed, are Well-known and'a few oflthe-many which4 may be mentioned include solid'phosphorie'acid, acid treated clays, liquid phosplfioricV or sulfuric acids, etc. The drawing illustrates' one embodiment in which the catalyst is a, solid materiali` packed in a reaction zone, in which case the `oler-ins in line 62 are supplied through valve 63 to heating coil 64 in furnace structuref'615. 'The' gases' are heated in coil 64 to the desired4 temperature and under thek desired pressure, depending upon the type of catalyst being; employed.` With solid phosphoric acid catalysts, temperatures of V15G-550 F. and pressures' off-,.100 toz-1500`pounds, or more, may be employd; Withliquidr` sulfuric. acid, temperatures 91180-200? F. and: preferably suiicient pressure to maintain liquid phase-conditions are employed. Theuhea'tediproducts'are supplied' through line S6 and valvexli :to catalyst-containing reactor4 68. 'I'hefv polymeri zatio'n'V products are Withdrawn therefrom through line 69 and valve10v and are supplied tostabilizer 58.`

The products supplied to stabilizer-58 are fractionated to produce a gasoline product f the desired vapor pressure andof relatively highoctane number, which product may be withdrawn through line 1I` andv valve 12 to storage or elsewhere, as desired. lThe stabilizer operates in the conventional manner, which 'is at pressures of 100 to 300 pounds but, as a feature of the invention, the gasoline produced in the cracking and coking operation is admixed with the gasoline produced in the polymerization operation 'and the mixture is subjected to stabilization in commingled state. The exact temperatures employed in the stabilization operation will depend upon the vapor pressure desired in the nal gasoline product, which vapor pressure will in turn depend upon the season of the year and the market requirements. If any components of the material supplied to the stabilizer are of higherboiling range than that desired in the nal gasoline, they may be separated in stabilizer 58 and removed therefrom through line 13 and valve 14. This material may be removed from the process or may be returned to any point in the system for further conversion. For the sake of simplicity, the stabilization operation is shown in the drawing as comprising a single column 4but may comprise .tWo or more columns, eachcontaining the conventional bubbletrays,A baffles, and the like. I have also omitted th'e conventional condensers, receivers, accumulators, as well as the return of a portion of the condensate from the overhead products of the stabilizerback to the stabilizer to serve as a coolingV and refluxing medium therein. These steps are conventional and are well-known in the artV so there islno need to complicate the drawing by `including vthem therein. Y l

The gaseous products `remaining unconverted in the polymerization step andconsisting, predominantly of parainic hydrocarbons are Withdrawn from stabilizer 58 through line 15.y A portion may be removed from the process through line 16 and valve 11, but at least a portion of these gases is supplied through valve 18, line 81, pump or compressor 88, line 89 and valve 90 to heating coil 19 in furnace structure 80. The light gases separated in fractionator and separator B are removed therefrom through line 8| and all or a portion may be removed from the process through line 82 andvalve 83. In some instances at least a portion -is supplied through valve 84, line 81, pumpor compressor 88, line 89 i and valve 90 to heating-coil 1S. rThe gases supplied to coil 19 may be heatedv therein to a temperature of 1l00-1400 F. at atmospheric `to 5000 pounds or more. VThese conditions are preferably regulated to effect interaction between these gases and also to provide them in the highly heated state so that, when they are supplied through line 85 and valve 86 and either line 40 and valve 4l to coke chamber I8 or line 42 and valve 43 to coke chamber 2 I, they will supply additional heat to assist in the coking operation. Under certain circumstances, the process may be operated so that at least a portion of the interaction between the gases and the vaporous products of the process will be effected withinrthe cokechambers. According to the present process, a less volatile coke product is obtained' than is normally produced in the conventional coking operations.` In addition to supplying va product Which is more desirable in certain instances, the

CTI

operation provides a greater amount of vaporous materialwhich may be subsequently condensed and subjected to additional cracking for the production of further quantities of gasoline.

. lAlthough the various heating coils are shown as positioned in separate furnace structures, it is. of course, `within the scope of the invention to include two vor more within a single furnace structure.V 1

It is thus seen bythe cooperative and interdependent steps. of the present process, the various components of the oil and gases are subjected to conversion under optimum conditions to produce maximum yields of the desired nal products of the process.

As an example of one specific operation, which may be conducted according to the present process, the primary charging stock may comprise topped crude-and'is separated in the fractionator andA separating zone into relatively light and heavy fractions. The heavy fraction may be heated to a temperature of 975 F. at 200 pounds. The light fraction may be heated to a temperature of 1050c F. at a pressure of 500 pounds. A

. secondary naphtha charging stock may be heated to a temperature of l050 F. at a pressure of 500 pounds. The gaseous products supplied to heating coil 19 may be heated to a temperature of 1200 F. The 3 and 4 carbon atom molecules mai7 be polymerized in the presence of solid phosphoric acid catalyst at a temperature of 475 F. and at a pressure of 1000 pounds. An operation of this type may produce, based on the charging stocks, approximately 64% of final gasoline distillate of approximately 17 octane number and approximately 26% of low volatile coke.

I claim as my invention:

l. A process for the conversion of hydrocarbons which comprises fractionating a hydrocarbon oil in commingled state With vaporous conversion products produced in the process as hereinafter set forth, to separate a selected heavy fraction, a selected light fraction, a fraction boilingsubstantially within the range of gasoline, a C3'-C4 fraction and light gas fraction, heating said selected heavy fraction to a cracking temperature, heating said selected light fraction to an independently controlled more severe cracking temperature, introducing the heated fractions into a coke chamber, polymerizing the olefinic constituents of said Cs-C4 fraction, admixing said fraction boiling substantially within the `range of gasoline with the products from the polymerization step, subjecting the mixture to stabilization to separate unconverted gases, heating said unconverted gases to an elevated temperature in a separate heating zone and introducing them into the coke chamber, and subjecting-the vaporous conversion products evolved in the coke chamber to fractionation in commingled state with said hydrocarbon oil, as previously set forth.

2. A process for the conversion of hydrocarbons which comprises fractionating a hydrocarlloonoil in commingled state with vaporous conyversion products'produced in the process as hereinafter set forth, to lseparate a selected heavy fraction, a selected light fraction a fraction boilingy substantially Within the range of gasoline, a fraction consisting predominantly of 3 and 4 'carbon atom molecules and a lighter gaseous fraction, heating said selected heavy fraction to a cracking temperature, heating said selected ylight fraction to an independently controlled more severe cracking temperature, introducing the heated fractions into a colsechamber,I polymerizing the olefinic constituents of saidfraction consisting predominantly of v3 and 4 carboniatom molecules, 'admixing said fraction boiling substantially within the range of gasoline: with said products from the polymerization sten-.subjecting the mixture to stabilization in commingled state, admixing said lighter gaseous fraction with the normally gaseous products remaining. un.- converted in the'polymerization step and evolved in said stabilization operation, reacting the mixture of gases in a separate heating zone, introducin'g the last mentioned reaction products into thecoke chamber,- and subjecting vaporous conversion products evolved in the coke chamber to fractionation in commingled state with said hydrocarbon oil, as previously set forth.

3. A process for the conversion of hydrocarbons which comprises fractionating.y a hydrocarbon oil in commingled state with vaporous conversion products produced in the process as hereinafterset forth,- to separate a selected heavy fraction, a selected light fraction, a fraction boiling substantially within the range of gasoline, a fraction Iconsisting predominantly of 3 and 4 carbonatom molecules and a `lighter gaseous fraction heating said selected heavy fraction to a cracking temperature, heating said selected light fraction to independently controlled more severe cracking temperature, simultaneously heating a hydrocarbon oil of substantially gasoline boiling range to to a reforming temperature, introducing the heated materials into a coke chamber, polymerizing the oleinic constituents of said fraction consisting predominantly of 3 and 4 carbon atom molecules, admixing said fraction boiling substantially within the range of gasoline with the products from said polymerization step, subjectingA the mixture to stabilization in cornmingledl state, admixing said lighter gaseous fraction with the' normally gaseous products remaining unconverted in the polymerization step and evolved in said stabilization operation, reacting the mixture of gases in a separate heating zone and introducing the reaction products therefrom into the coke chamber, and subjecting vaporous conversion products evolved the coke chamber to fractionation in commingled state with said hydrocarbon oil, as previously set forth.

4. A process for the conversion of hydrocarbons which comprises fractionating a hydrocarbon oil in commingled state with vaporous conversion products produced in the process as hereinafter set forth, to separate a selected heavy fraction, a selected light fraction, a fraction boiling substantially within the range of gasoline, a fraction consisting predominantly of 3 and-4icarbon atom molecules and a lighter gaseous fraction, heating said selected heavy fraction to a cracking temperature, heating said selected light fraction to independently controlled more severe cracking temperature, introducing the heated fractions into the upper portion of a, coke chamber, polymerizing the olenic constituents of said fraction consisting predominantly of 3 and 4 carbon atom molecules, admixing said fraction boiling substantially within the range of gasoline with the products from said polymerization step, subjecting the mixture to stabilization in commingled state, admixing said lighter gaseous fraction with the normally gaseous products remaining unconverted in the polymerization step and evolved in said stabilizationv operation, reacting the mixture of gasesA in a separate heating zone andintroducing reaction products therefrom into the lower portion of the coke chamber, andI sub- -jecting vaporousI conversion productsv evolved in the coke chamber to fractionation in commingled state with said hydrocarbon oil, as previously set forth. Y f

5. A process for the conversion of hydrocarbons which comprisesf'fractionating a hydrocarbon oil in commingledistat'e with vaporous conversion products produced in lthe process as hereinafter set forth, to separate a selected heavy fraction, a selected lightfraction, va fraction boiling substantially Within the-range of gasoline, a fraction consisting predominantly of 3 and 4 carbon atom molecules and a lighter gaseous fraction, heating said selected heavy fraction to a cracking temperature, heating said-selected light fraction to independently controlled more severe cracking temperature, simultaneously heating a hydrocarbon oil ofv substantially gasoline boiling range-to a reforming temperature, introducing' the'heated materials into the upper'portion--of a cokechamber, polymerizing the olefinic constituents of said fraction consistingy ypredominantly of`3 and 4 carbon atom molecules, admixing said fraction boiling substantially within the range of gasoline with the products from said polymerization step, subjecting 'the mixture to stabilization in eommingled state, admixing said lighter gaseous fraction with the normally gaseous products remaining unconverted 'in the polymerization step and evolved in said stabilization operation, reacting the mixture of gases in a n separate heating zone and introducing thereaction product' into the lower portion of the coke chamber, and subjecting vaporous conversion products evolved in the coke 'chamber to'v fractionation in commingled state' with said hydrocarbon oil, as previously-set forth.

6. A process for the conversion of hydrocarbons which comprises fractionating l a hydrocarbon oil incommingled state with vaporous conversion products produced in the process as hereinafter setr forth, to separate a selected heavy fraction, a selected light fraction, a fractionl boiling substantially within the range of gasoline, a fraction consisting predominantly of 3` and 4 carbon 'atom molecules and a lighter gaseous fraction, heating said selected heavy fraction to a cracking temperature, introducing the heated stream into the upper portion of va coke chamber, heating' said selected light fraction to independently controlled more severe cracking temperature, introducing the heated stream into the lower vportionv of the coke chamber, polymerizing the oleiinic constituents of said fraction consisting predominantly of 3 and 4 carbon atommolecules, admixing said fraction boiling substantially within the range of gasoline with the products from said polymerization step, subjecting the mixture to.

stabilization in commingled state, admixing said lighter gaseous fraction with the normally gaseous products remaining unconverted in the polymerization step andevolved in said stabilization operation, reacting the mixture of gases in a separate heating zone and 'introducing' the reaction products into the lower portion of the coke chamber, and subjecting vaporous conversion products evolved in the coke chamber to fractionation in commingled state with said hydrocarbon oil, as previously setrv forth.

7. Aprocess for the conversion of hydrocarbons which comprises fractionating a hydrocarbonoil in commingledl state with vvaporous conversion set forth, to separate a selected heavyy fraction, `a selected light fractioni a fraction `boiling subproducts produced in the process as hereinafter y stantially within the range of gasoline, a, fraction consisting predominantly of 3 and 4 ycarbon atom molecules and a lighter gaseous fraction, heating said selected heavy fraction to a cracking temperature, introducing'the heated stream into the"` upper portion of va coke chamber, heating said selected light fraction to an independently coni trolled more severe cracking temperature and introducing it into the lower portion of the coke chamber, polymerizing the oleiinic constituents of said fraction consisting predominantly of 3 subjecting vaporous conversion products evolved and 4 carbon atom molecules, admixing said frac- 15 in the c oke chamber to fractionation in .commingled state With said hydrocarbon oil, as previ-` ously set forth.

l GUSTAV EGLOEF. j 

